One of the most common symptoms reported by people attempting to quit smoking is craving for cigarettes. Laboratory and clinical studies have shown that reports of tobacco craving increase during periods of abstinence and that craving predicts relapse in smokers trying to quit. Thus, tobacco craving appears to play a significant role in the maintenance of nicotine dependence and treatment outcome. The primary objective of this study was to compare the effectiveness of active imagery versus in vivo cues in eliciting self-report and physiological responses indicative of tobacco craving. This study will also examine the effect of nicotine deprivation on cue-elicited craving, the duration of craving responses after cue manipulation, and the effect of nicotine deprivation on the attentional blink task. This study will establish a human laboratory model for investigating self-report and physiological responses to smoking cues. This model will be used in future studies to compare responses among various smoker groups (e.g., nicotine-dependent smokers, occasional smokers, former smokers) and smokers with co-morbid disorders, such as depression and schizophrenia. Smokers attend two experimental sessions, one in which they are at least 12 hours nicotine deprived and one in which they have been smoking normally. Never-smokers attend one experimental session. Experimental sessions begin with performance of the attentional blink task, which reflects a failure of the visual system to detect two target stimuli presented in rapid succession. This will be followed by four experimental trials, which will be presented in random order; each trial will last 30 minutes. The four trials are: 1) imagery script consisting of smoking descriptors, 2) imagery script with no smoking descriptors, 3) in vivo smoking cues, and 4) in vivo neutral cues. Participants will complete self-report measures of craving and have physiological measures taken immediately and 5, 10, 20, and 30 minutes after script or cue exposure. There will be a 5-10 minute rest period between trials. Primary outcome measures include self-report (Tobacco Craving Questionnaire and Visual Analog Scale questions) and physiological (heart rate, blood pressure, finger temperature, and skin conductance) variables. A secondary outcome measure is the number of correct target detections on the attentional blink task.